Instrumentation and Monitoring
Structural Soils Limited are able to install and monitor a wide range of geotechnical and geoenvironmental instrumentation. These can be for a variety of applications, such as ground movement, groundwater and ground gas monitoring.
With regard to ground movement, one of the simplest techniques is installing and monitoring the level of settlement plates set into the ground. More sophisticated monitoring of ground movements includes the use of extensometers with target magnets placed at multiple levels in boreholes, and borehole inclinometers which are monitored using a biaxial probe.
We are able to install the full range of groundwater and gas monitoring instruments, including standard standpipes piezometers set in sand cells within boreholes and slotted standpipes typically from 19mm up to 50mm internal diameter, although larger sizes are available. Groundwater levels are measured using a graduated dipmeter and ground gases monitored using an infra red analyser. When measuring gas concentrations, both initial and steady state levels are recorded together with atmospheric and installation pressure and flow rate. If long term groundwater information is required or the variation in water level over a tidal cycle, divers are installed in the piezometers/standpipes which are later collected and the data downloaded.
In addition to conventional groundwater piezometers, vibrating wire piezometers may installed. These are particularly useful where monitoring of piezometric levels in low permeability soils are required. The instruments are grouted into the boreholes and may either be monitored by hand at discrete times or data recorders provided which can record the piezometric data at prescribed intervals over many days or even months.